plasmoid: port away from custom drag handler

BUG: 464528
CCBUG: 402376

plasmoid/package/contents/ui/main.qml

@@ -598,7 +598,9 @@ Item {
     TaskManagerApplet.DragHelper {
         id: dragHelper
 
-        dragIconSize: units.iconSizes.medium
+        Drag.dragType: Drag.Automatic
+        Drag.supportedActions: Qt.CopyAction | Qt.MoveAction | Qt.LinkAction
+        Drag.onDragFinished: root.dragSource = null;
     }
 
     TaskManager.VirtualDesktopInfo {
@@ -1273,11 +1275,6 @@ Item {
         return false;
     }
 
-    function resetDragSource() {
-        dragSource.z = 0;
-        dragSource = null;
-    }
-
     ///REMOVE
     /*function createContextMenu(task) {
         var menu = root.contextMenuComponent.createObject(task);
@@ -1307,7 +1304,6 @@ Item {
         }
 
         root.windowsHovered.connect(backend.windowsHovered);
-        dragHelper.dropped.connect(resetDragSource);
         updateListViewParent();
     }
 
@@ -1319,7 +1315,6 @@ Item {
         }
 
         root.windowsHovered.disconnect(backend.windowsHovered);
-        dragHelper.dropped.disconnect(resetDragSource);
     }
 
     //BEGIN states

plasmoid/package/contents/ui/task/TaskItem.qml

@@ -328,9 +328,15 @@ AbilityItem.BasicItem {
 
     onIsDraggedChanged: {
         if (isDragged){
-            root.dragSource = taskItem;
+            taskItem.contentItem.monochromizedItem.grabToImage((result) => {
-            dragHelper.startDrag(taskItem, model.MimeType, model.MimeData,
+                root.dragSource = taskItem;
-                                 model.LauncherUrlWithoutIcon, model.decoration);
+                dragHelper.Drag.imageSource = result.url;
+                dragHelper.Drag.mimeData = dragHelper.generateMimeData(model.MimeType, model.MimeData, model.LauncherUrlWithoutIcon);
+                dragHelper.Drag.active = true;
+            });
+        } else {
+            dragHelper.Drag.active = false;
+            dragHelper.Drag.imageSource = "";
             pressX = -1;
             pressY = -1;
         }

plasmoid/package/contents/ui/task/TaskMouseArea.qml

@@ -81,12 +81,15 @@ MouseArea {
             // mouse.button is always 0 here, hence checking with mouse.buttons
             if (pressX != -1 && mouse.buttons == Qt.LeftButton
                     && isDragged
-                    && dragHelper.isDrag(pressX, pressY, mouse.x, mouse.y) ) {
+                    && (Math.abs(pressX - mouse.x) + Math.abs(pressY - mouse.y) >= Qt.styleHints.startDragDistance) ) {
-                root.dragSource = taskItem;
+                taskItem.contentItem.monochromizedItem.grabToImage((result) => {
-                dragHelper.startDrag(taskItem, model.MimeType, model.MimeData,
+                    pressX = -1;
-                                     model.LauncherUrlWithoutIcon, model.decoration);
+                    pressY = -1;
-                pressX = -1;
+                    root.dragSource = taskItem;
-                pressY = -1;
+                    dragHelper.Drag.imageSource = result.url;
+                    dragHelper.Drag.mimeData = dragHelper.generateMimeData(model.MimeType, model.MimeData, model.LauncherUrlWithoutIcon);
+                    dragHelper.Drag.active = true;
+                });
             }
         }
     }